Azo dyestuffs and process of making same



@atented Feb. 3, 1931 MAX SCHMID, OF RIEHEN, NEAR BASEL, AND FRITZ STRAUB, OF BASEL, S'WITZERLAND,

ASSIGNORS TO SOCIETY OF CHEMICAL INDUSTRY IN BASLE, F BASEL, SYVITZER- LAND AZO DYESTUFETS AND 0F IvI.-5.KING SAME No Drawing. Application filed July 19, 1928, Serial No. 294,044, and in Switzerland July 26, 1927.

This invention relates'to the manufacture of new dyestuii's by coupling a diazo-compound containing an Old-group in ortho-position to the diazogroup with pyrazolone derivatives of the general formula wherein R signifies hydrogen or alkyl, and which are produced by the condensation of an oXalo-acetic acid ester with hydrazine. Such pyrazolone derivatives are for instance the -.pyraZolone-3-carboxylic acid and the methyl or the ethyl ester of'this acid.

The azodyestufi's thus obtained correspond with the general formula wherein R means an aromatic complex con taining an OH-group in ortho-position to the azo-bridge and R has the signification as above stated. The products are yellow to orange or dark brown powders which dissolve in the suitable solvents with yellow to orange, red or brown colorations.

The products thus obtained may be further converted by treatment with agents yielding metal, such as copper compounds or chromium compounds, into dyestuffs containing metal which themselves have valuable dyeing properties.

w If one intends to produce mordant dyestufis which may also be used for the manufacture of dysteuifs containing metal, one will start from such diazo-compounds which contain in ortho-position to the diaZo-group an OH-group. Here there are particularly valuable those dyestuffs which derive from the 5-pyrazolone-3-carboXylic acid and from the sulfonated, if necessary also halogenated, diam-compounds. The dyestuffs so obtainable correspond with the general formula wherein R means any aromatic complex that carries in ortho-position to the diazogroup an OH-group, and R means hydrogen or alkyl. They constitute orange to brownred powders which are soluble in dilute sodium carbonate solution with yellow to orange and brown coloration.

The following-examples illustrate the invention, the parts being by weight Example 1 22.3 parts of 4-chloro-2-aminophenol-6- sulfonic acid are diazotized and coupled with 12.8 parts of 5-pyrazolone-3-carboxylic acid. The dyestull, which is salted out, forms a redbrown powder, dissolving in dilute sodium carbonate solution with brown coloration. It corresponds with the formula pyrazolone-3-carbo:-;ylie acid esters are some what brighter. lVith diazotized 1: Q-aminonaphthol-4-sulfonic acid or its nitro-derivative there is obtained dyestuii' which dyes 5 violet or lJOl'ClGZIUX on after-chroining. In

chrome printing on cotton the aforesaid dyestuff from diazotized l:Q-aminonaphtholesulfonic acid yields violet tints fast to washing.

lVhen these dyestuffs are treated with i there a e obtained and Viol and 5-pyraz YQfil in 1000 E remnple 5 17.3 parts of the dyestutf from nitrated l-diazo-Q-naphthol i-sulfonic acid and 5- pyrazolone-S-carboxylic acid ethyl ester are dissolved in 1000 parts of boiling water, m'iled with 22.8 parts of C130 in the form of a solution containing at per cent. of chromium fluoride, and then boiled until the dyestuil containing chromium has been formed. The same can be obtained by evaporation or by evaporation in part and saltiug out. It constitutes a blackish powder which dissolves in water and caustic soda solution of 10 per cent. strength to a blue-red solution and in concentrated sulfuric acid to a vi olet-brown solution, dyeing wool from a dyeing bath acidulated with sulfuric acid fast red tints. The manner in which the chromium is bound with the dyestufi is not known.

Example 1;

tutes a brown powder which dissolves in water and in aqueous caustic soda solution to a red solution, and in concentrated sulfuric acid to an orange solution, dyeing wool from abath acidulated with sulfuric acid fast red tints. The manner in which the chromium is bound with the dyestuif is not known.

Example 5 Goods are dyed with 1 per cent. of the dyestuff made as described in Example 4 from i-chloroaminophenol-tS-sulfonio acid and 5- pyrazolone-S-carboxylic acid with addition of 13 per cent. of acetic acid and 10 percent. of Glaubers salt. The goods are introduced at 60 (3., the bath is heated gradually to boiling and boiling is continued for to hour. The bath then receives an addition of 1-2 per cent. of sulfuric acid and boiling is continued for f hour. There is then added 1 per cent. of potassium bichromate and boilin g is further continued to develop fully the shade. The red dye thus obtained is characterized by its fastness to light. Dyeing may also be conducted in any other manner hitherto usual for dyeing with chrome dyestuiis.

hat we claim is 1. The manufacture of azo-dyestuifs by coupling pyrazolones of the general formula wherein R signifies hydrogen or an alkyl group, with diazo-compounds which contain in ortho-position to the diazo-group a hydroxyl group) 2. The manufacture of azo-dyestuifs by coupling pyrazolones of the general formula wherein R signifies hydrogen or an alkyl group, with diazo-compounds which contain in ortho-position to the diazo-group a hydroxyl group, and by treating the azo-dyestuffs thus obtained with agents yielding chromium.

3. As new products the azo-dyestufl's corresponding with the general formula wherein R means any aromatic complex that carries in ortho-position to the diazo-group a hydroXyl group, and R means hydrogen or alkyl, which constitute orange to brown-red powders which are soluble in dilute sodium carbonate solution with yellow to orange and brown coloration.

4. As new products the chromium compounds of azo-dyestufis of the general formula wherein R means any aromatic complex that carries in ortho-position to the diazo-group a hydroxyl group, and R means hydrogen or alkyl, which products form dark powders dissolving in water and dilute sodium carbonate solution with dark red to brown and violet coloration.

5. The material dyed with the dyestufls of claim 3.

6. The material dyed with the dyestuffs of claim 4:.

In witness whereof we have hereunto signed our names this 7th day of July, 1928.

MAX SCHMID. FRITZ STRAUB. 

